Pre-Purchase Geotech?

[Forester]

I'm looking to buy land in Puna. I heard about potential subsurface lava tubes, so I'd like to get a geotech study done before I buy a property. I spoke to Leslie's Drilling (a geotech company), however, and they told me that their study involves a large drill that would need access to the property. All the land I'm looking at is vacant and has pretty thick vegetation that would probably prohibit a large rig from accessing the property.

Is it possible for a geotech study to be done -- perhaps with smaller tools -- on these rainforest properties without any clearing being done? If so, can anyone recommend a geotech engineer who does this?